Belt drive washer

ABSTRACT

A drive mechanism for a washing machine having a basket rotatably mounted within a tub includes a variable speed motor including a first pulley. An agitator is mounted within the basket. A rotatable shaft has first and second ends. The first end is directly coupled to the agitator. A second pulley is mounted on the second end of the shaft. A drive belt connects the first pulley to the second pulley. An inverter is operatively coupled to the motor. A controller is operatively coupled to the inverter and the motor. The controller is configured to control the motor based on a predetermined agitation profile.

BACKGROUND OF THE INVENTION

This invention relates generally to washing machines, and moreparticularly, to belt driven washers having no transmission.

Washing machines typically include a cabinet that houses an outer tubfor containing wash and rinse water, a perforated clothes basket withinthe tub, and an agitator within the basket. A drive motor andtransmission assembly is mounted underneath the stationary outer tub torotate the basket and the agitator relative to one another and a pumpassembly pumps water from the tub to a drain to execute a wash cycle.

Generally, the transmission provides gear reduction from the motor foragitate and spin functions. However, known washer transmissions includerather inflexible washer platforms. For example, the transmissionstypically have a non-variable agitator motion, including stroke, ramprate, arc, and range rate. Generally, with a transmission, only theagitation rate or speed can be changed without changing thetransmission. Furthermore, the transmission adds to the part count andthe overall complexity of the washer drive mechanism.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, a drive mechanism for a washing machine having a basketrotatably mounted within a tub is provided. The drive mechanism includesa variable speed motor including a first pulley. An agitator is mountedwithin the basket. A rotatable shaft has first and second ends. Thefirst end is directly coupled to the agitator. A second pulley ismounted on the second end of the shaft. A drive belt connects the firstpulley to the second pulley. An inverter is operatively coupled to themotor. A controller is operatively coupled to the inverter and themotor. The controller is configured to control the motor based on apredetermined agitation profile.

In another aspect, A washing machine is provided that includes acabinet, a tub mounted within the cabinet, and a basket rotatablymounted within the tub for relative rotation therewith. An agitator ispositioned within and coupled to the basket such that the agitator andthe basket are rotatable without relative motion therebetween. Avariable speed motor includes a first pulley. A rotatable shaft hasfirst and second ends. The first end is directly coupled to theagitator, and a second pulley is mounted on the second end of the shaft.A drive belt connects the first pulley to the second pulley. An inverteris operatively coupled to the motor. A controller is operatively coupledto the inverter and the motor. The controller is configured to controlthe motor based on a predetermined agitation profile.

In yet another aspect, a washing machine is provided that includes acabinet, a tub mounted within the cabinet, and a basket rotatablymounted within the tub for relative rotation therewith. An agitator isrotatably mounted within the basket. A variable speed motor includes afirst pulley. A rotatable shaft has first and second ends. The first endis directly coupled to the agitator, and a second pulley is mounted onthe second end of the shaft. A drive belt connects the first pulley tothe second pulley. An inverter is operatively coupled to the motor. Acontroller is operatively coupled to the inverter and the motor. Thecontroller is configured to control the motor based on a predeterminedagitation profile.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective cutaway view of an exemplary washing machine.

FIG. 2 is front elevational schematic view of the washing machine shownin FIG. 1.

FIG. 3 is a schematic block diagram of a control system for the washingmachine shown in FIGS. 1 and 2.

FIG. 4 is a fragmentary view showing an exemplary belt drive system.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a perspective view partially broken away of an exemplarywashing machine 50 including a cabinet 52 and a cover 54. A backsplash56 extends from cover 54, and a control panel 58 including a pluralityof input selectors 60 is coupled to backsplash 56. Control panel 58 andinput selectors 60 collectively form a user interface input for operatorselection of machine cycles and features, and in one embodiment adisplay 61 indicates selected features, a countdown timer, and otheritems of interest to machine users. A lid 62 is mounted to cover 54 andis rotatable about a hinge (not shown) between an open position (notshown) facilitating access to a wash tub 64 located within cabinet 52,and a closed position (shown in FIG. 1) forming a sealed enclosure overwash tub 64. As illustrated in FIG. 1, machine 50 is a vertical axiswashing machine.

Tub 64 includes a bottom wall 66, a sidewall 68, and a basket 70 that isrotatably mounted within wash tub 64. A pump assembly 72 is locatedbeneath tub 64 and basket 70 for gravity assisted flow when draining tub64. Pump assembly 72 includes a pump 74 and a motor 76. A pump inlethose 80 extends from a wash tub outlet 82 in tub bottom wall 66 to apump inlet 84, and a pump outlet hose 86 extends from a pump outlet 88to an appliance washing machine water outlet 90 and ultimately to abuilding plumbing system discharge line (not shown) in flowcommunication with outlet 90.

FIG. 2 is a front elevational schematic view of washing machine 50including wash basket 70 movably disposed and rotatably mounted in washtub 64 in a spaced apart relationship from tub side wall 64 and tubbottom 66. In one embodiment, basket 70 includes a plurality ofperforations therein to facilitate fluid communication between aninterior of basket 70 and wash tub 64. In an alternative embodiment,only a bottom 71 of basket 70 is perforated.

A hot liquid valve 102 and a cold liquid valve 104 deliver fluid, suchas water, to basket 70 and wash tub 64 through a respective hot liquidhose 106 and a cold liquid hose 108. Liquid valves 102, 104 and liquidhoses 106, 108 together form a liquid supply connection for washingmachine 50 and, when connected to a building plumbing system (notshown), provide a fresh water supply for use in washing machine 50.Liquid valves 102, 104 and liquid hoses 106, 108 are connected to abasket inlet tube 110, and fluid is dispersed from inlet tube 110through a known nozzle assembly 112 having a number of openings thereinto direct washing liquid into basket 70 at a given trajectory andvelocity. A known dispenser (not shown in FIG. 2), may also be providedto produce a wash solution by mixing fresh water with a known detergentor other composition for cleansing of articles in basket 70.

In an alternative embodiment, a known spray fill conduit 114 (shown inphantom in FIG. 2) may be employed in lieu of nozzle assembly 112. Alongthe length of spray fill conduit 114 are a plurality of openingsarranged in a predetermined pattern to direct incoming streams of waterin a downward tangential manner towards articles in basket 70. Theopenings in spray fill conduit 114 are located a predetermined distanceapart from one another to produce an overlapping coverage of liquidstreams into basket 70. Articles in basket 70 may therefore be uniformlywetted even when basket 70 is maintained in a stationary position.

A known agitation element 116 is mounted within basket 70. Asillustrated in FIG. 2, agitation element 116 is oriented to rotate abouta vertical axis 118. Basket 70 and agitator 116 are driven by a variablespeed motor 120. An inverter 121 is operatively coupled to motor 120 andis configured to control motor 120 in response to signals from acontroller 138 (FIG. 3). A drive belt 124 is coupled to respectivepulleys of a motor output shaft 126 and an agitator input shaft 128 aswill be described. In one embodiment, a clutch system 122 facilitatesdriving engagement of basket 70 and agitation element 116 for rotatablemovement within wash tub 64, and clutch system 122 facilitates relativerotation of basket 70 and agitation element 116 for selected portions ofwash cycles. Motor 120, clutch system 122, when present, and agitationelement 116 collectively are referred to herein as a machine drivesystem 148. Washing machine 50 does not include a transmission.

Pump assembly 72 is selectively activated to remove liquid from basket70 and tub 64 through drain outlet 90 and a drain valve 130 duringappropriate points of washing cycles. In an exemplary embodiment,machine 50 also includes a reservoir 132, a tube 134, and a pressuresensor 136. As fluid levels rise in wash tub 64, air is trapped inreservoir 132 creating a pressure in tube 134, that pressure sensor 136monitors. Liquid levels, and more specifically, changes in liquid levelsin wash tub 64 may therefore be sensed, for example, to indicate laundryloads and to facilitate associated control decisions. In further andalternative embodiments, load size and cycle effectiveness may bedetermined or evaluated using other known indicia, such as motor spin,torque, load weight, motor current, and voltage or current phase shifts.

Operation of machine 50 is controlled by a controller 138 which isoperatively coupled to the user interface input located on washingmachine backsplash 56 (shown in FIG. 1) for user manipulation to selectwashing machine cycles and features. In response to user manipulation ofthe user interface input, controller 138 operates the various componentsof machine 50 to execute selected machine cycles and features.

The washing operation is initiated through operator manipulation ofcontrol input selectors 60 (shown in FIG. 1). In one embodiment, washingmachine 50 is a direct drive washer that is configured to provide abasket wash wherein laundry items are washed by oscillating basket 70and agitator 116 together. That is, basket 70 and agitator 116 rotate asa unit with no relative motion therebetween. The mechanical wash actionis achieved by the relative motion between the laundry items and thebasket and agitator combination, 70 and 116 respectively, when tub 64 isfilled with a wash liquid. Basket 70 and agitation element 116 are movedback and forth in an oscillatory back and forth motion. In theillustrated embodiment, basket 70 and agitation element 116 are rotatedclockwise about the vertical axis 118 of the machine, and then rotatedcounterclockwise about the vertical axis 118. Theclockwise/counterclockwise reciprocating motion is sometimes referred toas a stroke, and the agitation phase of the wash cycle constitutes anumber of strokes in sequence. Acceleration and deceleration of basket70 and agitation element 116 during the strokes imparts mechanicalenergy to articles in basket 70 for cleansing action. In washing machine50, reversible motor 120 provides the stroke action during agitation ofthe laundry items. In some embodiments of the basket wash system, basket70 includes a perforated bottom 71 and non-perforated side walls.

In another embodiment, washing machine 50 agitator 116 and basket 70 arerotatable with respect to one another. In such embodiments, washingmachine 50 includes clutch 122 that is configured to lock and unlockbasket 70 and agitator 166 in response to signals from controller 138.During agitation, basked 70 is locked and agitator 116 oscillates withinbasket 70 to agitate the laundry items. Agitator 116 is directly drivenby reversing motor 120 without a transmission. This washing machinedesign, however, includes a conventional basket having perforated sidewalls.

After the agitation phase of the wash cycle is completed, tub 64 isdrained with pump assembly 72. Laundry items are then rinsed andportions of the cycle repeated, including the agitation phase, dependingon the particulars of the wash cycle selected by a user.

FIG. 3 is a schematic block diagram of an exemplary washing machinecontrol system 150 for use with washing machine 50 (shown in FIGS. 1 and2). Control system 150 includes controller 138 which may, for example,be a microcomputer 140 coupled to a user interface input 141. Anoperator enters instructions or selects desired washing machine cyclesand features via user interface input 141, such as through inputselectors 60 (shown in FIG. 1) and a display or indicator 61 coupled tomicrocomputer 140 displays appropriate messages and/or indicators, suchas a timer, and other known items of interest to washing machine users.A memory 142 is also coupled to microcomputer 140 and storesinstructions, calibration constants, and other information as requiredto satisfactorily complete a selected wash cycle. Memory 142 may, forexample, be a random access memory (RAM). In alternative embodiments,other forms of memory could be used in conjunction with RAM memory,including but not limited to flash memory (FLASH), programmable readonly memory (PROM), and electronically erasable programmable read onlymemory (EEPROM).

Power to control system 150 is supplied to controller 138 by a powersupply 146 configured to be coupled to a power line L. Analog to digitaland digital to analog converters (not shown) are coupled to controller138 to implement controller inputs and executable instructions togenerate controller output to washing machine components such as thosedescribed above in relation to FIGS. 1 and 2. More specifically,controller 138 is operatively coupled to machine drive system 148 (e.g.,motor 120, inverter drive 121, clutch system 122, and agitation element116 shown in FIG. 2), a brake assembly 151 associated with basket 70(shown in FIG. 2) which may be provided, machine water valves 152 (e.g.,valves 102, 104 shown in FIG. 2) and machine drain system 154 (e.g.,drain pump assembly 72 and/or drain valve 130 shown in FIG. 2) accordingto known methods. In a further embodiment, water valves 152 are in flowcommunication with a dispenser 153 (shown in phantom in FIG. 3) so thatwater may be mixed with detergent or other composition of benefit towashing of garments in wash basket 70.

FIG. 4 is a fragmentary view showing an exemplary belt drive system 200for a washing machine such as washing machine 50. Belt drive system 200includes reversible motor 120 having an output shaft 126 which includesa first pulley 202. A second pulley 204 is mounted on agitator inputshaft 128. Drive belt 124 interconnects first pulley 202 and secondpulley 204. Motor 120 is a direct drive motor that drives agitator 116without the use of a transmission. Pulleys 202 and 204 effectivelyprovide a gear reduction that eliminates the need for a transmission. Inan exemplary embodiment, drive belt 124 is a known V-belt that has ribsor grooves 208 on the under side. First pulley 202 on motor 120 isformed with mating grooves 210. In one embodiment, motor 120 may befabricated to include an output shaft with grooves 210 formed directlythereon.

First pulley 202 has a diameter D₁ and second pulley 204 has a seconddiameter D₂. When washing machine 50 is designed to provide the basketwash, the ratio of diameter D₂ to D₁ is at least twenty to one. Whenwashing machine 50 is designed to provide the conventional wash, theratio of diameter D₂ to D₁ is at least fifteen to one.

In response to manipulation of user interface input 141 controller 138monitors various operational factors of washing machine 50 with one ormore sensors or transducers 156, and controller 138 executes operatorselected functions and features according to known methods. Of course,controller 138 may be used to control washing machine system elementsand to execute functions beyond those specifically described herein.Controller 138 operates the various components of washing machine 50 ina designated wash cycle familiar to those in the art of washingmachines.

In one embodiment, controller 138 is configured to control motor 120 andinverter 121 based on a predetermined agitation profile. For washingmachine 50, controller 138 is programmed with one or more time basedagitation profiles that include predetermined stroke, speed, and ramprate parameters. The agitation profiles are time based rather thandisplacement based. More specifically, in the time based profile, eachstroke has a specified time interval rather than the more conventionaldisplacement distance. When strokes are displacement based, increasedmotor torque is required as load size increases. In washing machine 50,the stroke is shortened with the time based agitation profile so as toavoid over heating of motor 120.

Since motor 120 directly drives agitator 116, motor 120 changesdirection during the agitation cycle. In one embodiment, motor heat isreduced by allowing motor 120 to coast to a stop as direction changesoccur. That is, motor 120 is turned off and the motor is allowed to slowdown to reduce the amount of time that the motor is used as a brake. Inalternative embodiments, changes in agitator direction are accompaniedby a controlled ramp down with the motor running rather than turning themotor completely off.

The above described apparatus provides a drive system for washingmachines that eliminates a transmission. The system provides improvedreliability with a reduction in cost. Additionally, agitation parametersmay be changed without the need to replace the transmission.

While the invention has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

1. A drive mechanism for a washing machine having a basket rotatablymounted within a tub, said drive mechanism comprising: a variable speedmotor including a first pulley; an agitator mounted within the basket; arotatable shaft having first and second ends, said first end directlycoupled to said agitator; a second pulley mounted on said second end ofsaid shaft; a drive belt connecting said first pulley to said secondpulley; an inverter operatively coupled to said motor; and a controlleroperatively coupled to said inverter and said motor, said controllerconfigured to control said motor based on a predetermined agitationprofile.
 2. A drive mechanism in accordance with claim 1 wherein saidagitation profile is time based.
 3. A drive mechanism in accordance withclaim 2 wherein said agitation profile includes allowing the agitator tocoast to a stop with said motor turned off when changing the directionof rotation of the agitator.
 4. A drive mechanism in accordance withclaim 2 wherein said agitation profile includes a controlled stop of theagitator with the motor running when changing the direction of rotationof the agitator
 5. A drive mechanism in accordance with claim 2 whereinthe basket and the agitator move together during agitation with norelative motion therebetween.
 6. A drive mechanism in accordance withclaim 5 wherein said first pulley has a first diameter and said secondpulley has a second diameter and a ratio of said second diameter to saidfirst diameter is at least twenty to one.
 7. A drive mechanism inaccordance with claim 2 wherein the agitator rotatable with respect tothe basket and said drive mechanism further comprises a clutchoperatively coupled to the basket and said shaft, said controllercontrolling said clutch to lock and unlock the agitator to the basket.8. A drive mechanism in accordance with claim 7 wherein said firstpulley has a first diameter and said second pulley has a second diameterand a ratio of said second diameter to said first diameter is at leastfifteen to one.
 9. A washing machine comprising: a cabinet; a tubmounted within said cabinet; a basket rotatably mounted within said tubfor relative rotation therewith; an agitator positioned within andcoupled to said basket such that said agitator and said basket arerotatable without relative motion therebetween; a variable speed motorincluding a first pulley; a rotatable shaft having first and secondends, said first end directly coupled to the agitator; a second pulleymounted on said second end of said shaft; a drive belt connecting saidfirst pulley to said second pulley; an inverter operatively coupled tosaid motor; and a controller operatively coupled to said inverter andsaid motor, said controller configured to control said motor based on apredetermined agitation profile.
 10. A washing machine in accordancewith claim 9 wherein said first pulley has a first diameter and saidsecond pulley has a second diameter and a ratio of said second diameterto said first diameter is at least twenty to one.
 11. A washing machinein accordance with claim 9 wherein said agitation profile is time based.12. A washing machine in accordance with claim 11 wherein said agitationprofile includes allowing the agitator to coast to a stop with saidmotor turned off when changing the direction of rotation of theagitator.
 13. A washing machine in accordance with claim 11 wherein saidagitation profile includes a controlled stop of the agitator with themotor running when changing the direction of rotation of the agitator.14. A washing machine comprising: a cabinet; a tub mounted within saidcabinet; a basket rotatably mounted within said tub for relativerotation therewith; an agitator rotatably mounted within said basket; avariable speed motor including a first pulley; a rotatable shaft havingfirst and second ends, said first end directly coupled to the agitator;a second pulley mounted on said second end of said shaft; a drive beltconnecting said first pulley to said second pulley; an inverteroperatively coupled to said motor; and a controller operatively coupledto said inverter and said motor, said controller configured to controlsaid motor based on a predetermined agitation profile.
 15. A washingmachine in accordance with claim 14 wherein said first pulley has afirst diameter and said second pulley has a second diameter and a ratioof said second diameter to said first diameter is at least fifteen toone.
 16. A washing machine in accordance with claim 14 wherein saidagitation profile is time based.
 17. A washing machine in accordancewith claim 16 wherein said agitation profile includes allowing theagitator to coast to a stop with said motor turned off when changing thedirection of rotation of the agitator.
 18. A washing machine inaccordance with claim 16 wherein said agitation profile includes acontrolled stop of the agitator with the motor running when changing thedirection of rotation of the agitator.